Marseilles

wiktionary

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From French Marseille, from Latin Massilia, Marsilia, from Ancient Greek Μασσαλία(Massalía), probably from a pre-Latin language of Italy, perhaps Ancient Ligurian mas(“spring”). The r was probably retained from Arabic مَرْسَى‎ (marsā, “harbor”).

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “where did the English -s come from?”)

etymonline

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Marseilles

also Marseille, city in southern France, from French Marseille, ultimately from Greek Massilia, which is probably from a pre-Latin language of Italy, perhaps Ligurian mas "spring." Related: Massilian "of or belonging to Marseilles."